The occurrence and development of tumor relate to hypofunction of immune surveillance, some infections could be effectively prevented by administration of vaccines against pathogenic microorganism, and immune tolerance could be restored by immune regulation or induction of immune tolerance in autoimmune diseases caused by autoimmune tolerance impairment. All these immunologic intervention means relate to antigens or antibodies, while most of antigens or antibodies are proteins. Hence, the above immunologic intervention means primarily aim at inducing immunoreaction against or immune tolerance to antigen proteins or taking full advantage of targeting ability of antibodies.
The key to achieve the aforesaid immunologic intervention is how to efficiently convey antigen protein to lymphatic tissue. If an antigen protein is effectively and firmly coupled to the surface of an immune cell, the antigen protein could be efficiently conveyed to lymphatic tissue or presented better via infusion of the immune cell because the immune cell has feature of immigrating to and positioning at lymphatic tissue or feature of presenting an antigen. Alternatively, immune effector cells could be anchored at target cells by using targeting ability of antibody, so as to improve killing efficiency of the immune effector cells.
One of known methods of coupling a protein to cell membrane comprises coupling a known antigen to cell surface by cell fixation with ethylene carbodiimide (ECDI) (luo, et al. Proc Natl AcadSci USA. 2008 Sep. 23; 105 (38):14527-32.; Smarr C B, et al. Antigen-fixed leukocytes tolerize Th2 responses in mouse models of allergy. J Immunol. 2011 Nov. 15; 187 (10):5090-8.). The cells prepared by this method are dead due to ECDI fixation, and according to this article, the infusion of these cells could only induce antigen specific immunologic tolerance, but could not induce immunologic response to the antigen.
Hence, it is still in need in the art to provide a method of coupling a protein to a living cell, so as to induce more efficiently the immunologic response useful in prophylaxis or treatment of infection and tumors.
Contents of the Invention
After long-term and a large amount of experimental researches, the inventors of the present invention surprisingly found that a protein could be coupled to a cell by using a bifunctional cross-linking agent, wherein the activities of the protein and the cell are maintained, thereby fulfilling the present invention.
The first aspect of the present invention relates to a protein-cell conjugate, which is a conjugate formed by covalently linking a protein and a cell to a linker, respectively; preferably, the cell has free sulfhydryl groups distributed on its surface, when the cell is not linked to the linker; preferably, the linker is derived from a bifunctional cross-linking agent, and the bifunctional cross-linking agent comprises both a group capable of reacting with an amino group and a group capable of reacting with a sulfhydryl group.
According to the protein-cell conjugate of any item of the first aspect of the present invention, wherein the cell is a cell with immunologic function; preferably, the cell is at least one selected from the group consisting of lymphocytes, monocytes, macrophages, dendritic cells, and natural killer cells.
In some embodiments of the present invention, the cell is lymphocyte, and for example, the lymphocyte is T lymphocyte or B lymphocyte.
According to the protein-cell conjugate of any item of the first aspect of the present invention, wherein the linker is derived from a bifunctional cross-linking agent.
In some specific embodiments of the present invention, the bifunctional cross-linking agent comprises both a succinimidyl group and a maleimidyl group.
In some embodiments of the present invention, any compounds comprising both succinimidyl group and maleimidyl group can fulfill the present invention. In some specific embodiments of the present invention, the compounds include but are not limited to succinimidyl4-(N-maleimidomethyl)-cyclohexane-1-carboxylate (SMCC) or analogues thereof, N-succinimidyl-4-(N-maleimidomethyl)-cyclohexane-1-carboxy-(6-aminocaproate), which is a long-chain analogue of SMCC (LC-SMCC), (N-maleimidomethyl)-cyclohexane-1-carboxylic acid-3-sulfosuccinimide ester (SULFO-SMCC), κ-maleimido-undecanoic acid N-succinimidyl ester (KMUA), γ-maleimidobutyric acid N-succinimidyl ester (GMBS), ε-maleimidocaproic acid N-hydroxysuccinimidyl ester (EMCS), meta-maleimidobenzoyl-N-hydroxysuccinimide ester (MBS), N-(α-maleimidoacetoxy)-succinimide ester (AMAS), succinimidyl-6-(β-maleimidopropionylamino)hexanoate (SMPH) or N-succinimidyl 4-(para-maleimidophenyl)-butyrate (SMPB).
According to the protein-cell conjugate of any item of the first aspect of the present invention, the succinimidyl of the bifunctional cross-linking agent reacts with a free amino group of the protein to form an amido linkage, and the maleimidyl of the bifunctional cross-linking agent reacts with the free sulfhydryl group on the cell to form a thioether linkage.
According to the protein-cell conjugate of any item of the first aspect of the present invention, the protein includes but is not limited to antigen proteins (e.g., tumor associated antigens, antigens associated with infectious diseases, antigens associated with autoimmune diseases), epitopes, antibodies, hormones, growth factors, vitamins, colony stimulating factors.
In an embodiment of the present invention, the protein is keyhole limpet hemocyanin (KLH); in another embodiment, the protein is insulin. In another embodiment, the protein is liver cancer associated protein, glypican-3 (GPC3).
The second aspect of the present invention relates to a method for preparing a protein-cell conjugate, which comprises the following steps:
(1) contacting a protein with a bifunctional cross-linking agent so that a linking group of the bifunctional cross-linking agent covalently links to the protein, thereby obtaining a first mixture, which comprises the protein linked to the linking group;
(2) optionally, further comprising a step of removing the unlinked bifunctional cross-linking agent from the first mixture, to obtain a purified protein linked to the linking group;
(3) contacting the protein linked to the linking group obtained in step (1) or (2) with a cell, so that another linking group covalently links to the cell, thereby obtaining a second mixture, which comprises a conjugate of the protein and the cell which covalently link to the linker separately, i.e., the protein-cell conjugate;
(4) optionally, further comprising a step of removing the protein that does not link to the cell from the second mixture, to obtain a purified second mixture comprising the protein-cell conjugate;
Or which comprises the following steps:
(a) contacting a cell with a bifunctional cross-linking agent so that a linking group of the bifunctional cross-linking agent is covalently linked to the cell, thereby obtaining a first mixture, which comprises the cell linked to the linking group;
(b) optionally, further comprising a step of removing the unlinked bifunctional cross-linking agent from the first mixture, to obtain a purified cell linked to the linking group;
(c) contacting the cell linked to the linking group obtained in step (a) or (b) with a protein, so that the linking group covalently links to the protein, thereby obtaining a second mixture, which comprises a conjugate of the protein and the cell which covalently link to the linker separately, i.e., the protein-cell conjugate;
(d) optionally, further comprising a step of removing the protein that does not link to the cell from the second mixture, to obtain a purified second mixture comprising the protein-cell conjugate;
preferably, the cell has free sulfhydryl groups distributed on its surface, when the cell is not linked to the linker
preferably, the bifunctional cross-linking agent comprises both a group capable of reacting with amino group and a group capable of reacting with sulfhydryl group.
According to the method of any item of the second aspect of the present invention, the cell is a cell with immunologic function; preferably, the cell is at least one selected from the group consisting of lymphocytes, monocytes, macrophages, dendritic cells, and natural killer cells.
In some embodiments of the present invention, the bifunctional cross-linking agent comprises both a succinimidyl group and a maleimidyl group. Any compounds comprising both succinimidyl group and maleimidyl group can fulfill the present invention.
In some specific embodiments of the present invention, the bifunctional cross-linking agent includes but is not limited to succinimidyl 4-(N-maleimidomethyl)-cyclohexane-1-carboxylate (SMCC) or analogues thereof, N-succinimidyl-4-(N-maleimidomethyl)-cyclohexane-1-carboxy-(6-aminocaproate), which is a long-chain analogue of SMCC (LC-SMCC), (N-maleimidomethyl)-cyclohexane-1-carboxylic acid-3-sulfosuccinimide ester (sulfonic acid group SMCC, SULFO-SMCC), κ-maleimidoundecanoic acid N-succinimidyl ester (KMUA), γ-maleimidobutyric acid N-succinimidyl ester (GMBS), ε-maleimidocaproic acid N-hydroxysuccinimidyl ester (EMCS), meta-maleimidobenzoyl-N-hydroxysuccinimide ester (MBS), N-(α-maleimidoacetoxy)-succinimide ester (AMAS), succinimidyl-6-(β-maleimidopropionylamino)hexanoate (SMPH) or N-succinimidyl 4-(para-maleimidophenyl)-butyrate (SMPB).
According to the method of any item of the second aspect of the present invention, the succinimidyl of the bifunctional cross-linking agent reacts with a free amino group of the protein to form an amido linkage, and the maleimidyl of the bifunctional cross-linking agent reacts with a free sulfhydryl group on the cell to form a thioether linkage.
According to the method of any item of the second aspect of the present invention, the protein includes but is not limited to antigen proteins (e.g., tumor associated antigens, antigens associated with infectious diseases, antigens associated with autoimmune diseases), epitopes, antibodies, hormones, growth factors, vitamins, colony stimulating factors.
In an embodiment of the present invention, the protein is keyhole limpet hemocyanin (KLH); in another embodiment, the protein is insulin. In another embodiment, the protein is liver cancer associated protein, glypican-3 (GPC3).
According to the method of any item of the second aspect of the present invention, it is characterized in one or more of the following items (1) to (4):
(1) the contacting is performed at a temperature of 4-40° C., preferably 6-37° C., more preferably 15-25° C., for example, room temperature;
(2) the contacting is performed for a time of 10-60 min, preferably 20-50 min, more preferably 30-40 min;
(3) the contacting is performed in a solution, which is for example a physiological saline solution or a buffer solution, wherein the buffer solution is for example phosphate buffer solution, citrate buffer solution, acetate buffer solution, succinate buffer solution, borate buffer solution, tartrate buffer solution, lactate buffer solution or carbonate buffer solution;
(4) the contacting is performed at a pH of 4.0-9.0, preferably 6.0-8.0, further preferably 6.5-7.5, more preferably 7.0-7.2.
In some embodiments of the present invention, the buffer solution is phosphate buffer solution (PBS).
In some embodiments of the present invention, the bifunctional cross-linking agent is dissolved in dimethyl sulfoxide.
The present invention further relates to use of the protein-cell conjugate of any one of items of the first aspect of the present invention in manufacturing of a medicament and/or vaccine, wherein the medicament and/or vaccine is used for prevention or treatment of one or more of the following diseases:
(1) diseases relevant to the protein in the protein-cell conjugate;
(2) malignant tumors;
(3) infectious diseases caused by pathogenic microorganisms;
(4) autoimmune diseases;
The present invention further relates to a method for prevention or treatment of one or more of the following diseases,
(1) diseases relevant to the protein in the protein-cell conjugate;
(2) malignant tumors;
(3) infectious diseases caused by pathogenic microorganisms;
(4) autoimmune diseases;
wherein the method comprises a step of administering to a subject in such need a prophylactically or therapeutically effective amount of the protein-cell conjugate of any one of the items of the first aspect of the present invention.
The present invention is described in details as follows.
In the present invention, the protein can be either an intact protein molecule, or a polypeptide with certain function such as epitope function, and the size of the polypeptide can be 8 to 100 amino acids, wherein an amino group of the protein or polypeptide can chemically react with a bifunctional cross-linking agent to form a covalent linkage.
In the present invention, the protein includes but is not limited to antigen proteins (e.g., tumors associated antigens, antigens associated with infectious diseases, antigens associated with autoimmune diseases), epitopes, antibodies, hormones, growth factors (e.g., IL-2, IL-3, IL-4, IL-6, EGF, TGF-α, VEGF, etc.), vitamins, colony stimulating factors(e.g., G-CSF, MCSF, GM-CSF, etc.).
When the protein is an antigen protein or an antigen epitope, the antigen protein can be conveyed to lymphatic tissue via the cell in the protein-cell conjugate, so as to improve the targeting ability of the antigen protein.
When the protein is an antibody, a hormone, a growth factor, etc., a killer cell can be conveyed to a target cell by utilizing the targeting ability of the antibody, etc., so as to improve the killing effect on the target cell. For example, tumor specific cytotoxic T cells can be brought to tumor by recognition of the surface antigen of tumor cells by an antibody, so as to improve the killing and scavenging effects of the cytotoxic T cells on tumor cells.
In some embodiments of the present invention, the antibody is a monoclonal antibody.
In the present invention, the antibody can be either an intact antibody, or its antigen binding site.
In the present invention, the cell is preferably a cell which has free sulfhydryl groups distributed on its surface, and the sulfhydryl groups can chemically react with a bifunctional cross-linking agent to form covalent linkages. It is well known by those skilled in the art that cells having sulfhydryl groups distributed on its surface include: lymphocytes (e.g., B cells, T cells), monocytes, macrophages, NK cells, dendritic cells, etc., (Matthias T Stephan, James J Moon, Soong Ho Um, et al. Therapeutic cell engineering with surface-conjugated synthetic nanoparticles. Nature Medicine, 2010, 16 (9), 1035-1042). These cells can be derived from blood (e.g., peripheral blood), or separated and obtained from tissues.
In the present invention, the cell can be a living cell or a dead cell (an apoptotic cell).
In the present invention, the cell can be a single kind of cells, or a mixture of a plurality of kinds of cells, for example, can be a mixture of T lymphocytes and B lymphocytes, or further comprise monocytes or other cellular components.
In the present invention, the method for separating and culturing the cell is well known in the art, for example, the cells can be separated from peripheral blood, or separated from bone marrow, or separated from tissues.
In some embodiments of the present invention, the cells are separated from a spleen, and the obtained spleen cells mainly comprise lymphocytes.
In the present invention, the linker in the protein-cell conjugate is a linking group formed after chemical reaction of a bifunctional cross-linking agent with a protein and a cell, respectively.
In the present invention, the bifunctional cross-linking agent refers to a compound comprising both a group capable of coupling to a protein (i.e., forming covalent linkage with a protein) and a group capable of coupling to a cell (i.e., forming covalent linkage with a cell).
In some embodiments of the present invention, the group capable of reacting with amino group can be used to couple the bifunctional cross-linking agent to a protein, while the group capable of reacting with sulfhydryl group can be used to couple the bifunctional cross-linking agent to a cell (see: FIG. 1).
In some embodiments of the present invention, the bifunctional cross-linking agent comprises both succinimidyl group and maleimidyl group, in which the succinimidyl group is used to couple the agent to a protein, and the maleimidyl group is used to couple the agent to a cell.
In some embodiments of the present invention, the succinimidyl group of the bifunctional cross-linking agent reacts with the free amino group of the protein to form an amide bond, while the maleimidyl group of the bifunctional cross-linking agent reacts with the free sulfhydryl group to form a thioether bond (see: FIG. 1).
In the present invention, the amide bond refers to —CO—NH—; in some embodiments of the present invention, the amide bond refers to a linkage formed by “click” chemical reaction between the succinimidyl group of SMCC and the free amino group of a protein molecule.
In the present invention, the thioether bond refers to R1—S—R2, wherein R is an organic group; in some embodiments of the present invention, the thioether bond refers to a covalent bond formed between the maleimidyl group and the free sulfhydryl group on cell membrane.
Other bifunctional cross-linking agents that are well known in the art but are not listed in the present invention, for example, cross-linking agents comprising both succinimidyl and maleimidyl groups, can also be used in the present invention.
In the present invention, the method for preparing the protein-cell conjugate comprises: a step of coupling a protein to a bifunctional cross-linking agent, and then a step of coupling the protein conjugated with the bifunctional cross-linking agent to a cell; preferably, further comprises a step of removing unlinked bifunctional cross-linking agent before coupling the protein to the cell, or preferably, further comprises a step of removing free protein coupled to the bifunctional cross-linking agent after coupling the protein to the cell; or
the method comprises: a step of coupling a cell to a bifunctional cross-linking agent, and then a step of coupling the cell coupled to the bifunctional cross-linking agent to a protein; preferably, further comprises a step of removing unlinked bifunctional cross-linking agent before coupling the cell to the protein, or preferably, further comprises a step of removing unlinked protein after coupling the cell to the protein.
In the present invention, a protein can be firstly coupled to a bifunctional cross-linking agent, then the protein conjugated with the bifunctional cross-linking agent is coupled to a cell; or a cell can be firstly coupled to a bifunctional cross-linking agent, then a protein is coupled to the cell conjugated with the bifunctional cross-linking agent.
In the present invention, the process of removing unlinked bifunctional cross-linking agent includes those process well known in the art, and can be chosen according to the size of the conjugate, for example, it can be tangential flow filtration (TFF), adsorption chromatography such as high pressure liquid chromatography, adsorption filtration, selective precipitation or dialysis.
In the present invention, the process of separating cells from free proteins is well known in the art, for example, the protein in cell-containing solution can be removed by centrifugation.
In some embodiments of the present invention, the coupling reaction between the bifunctional cross-linking agent and the protein or cell is performed in a solution. The reaction solution can be chosen according to properties of the protein and the cell by a skilled person in the art. In some embodiments of the present invention, the reaction is performed in a phosphate buffer solution. In some embodiments of the present invention, the bifunctional cross-linking agent is dissolved in dimethyl sulfoxide.
In the present invention, the term “coupling” refers to forming a covalent linkage via chemical reaction between two molecules or between a molecule and a cell.
In the present invention, the buffer solution refers to a solution which is prepared from a buffer pair consisting of “weak acid and its conjugate base” or “weak base and its conjugate acid”, and is capable of reducing pH change when an amount of other substance is added.
In the present invention, the diseases associated with the protein can be for example tumor-antigen protein associated tumors, or infectious diseases relating to known specific surface antigen proteins of pathogenic microorganisms, or autoimmune diseases relating to autoantigen proteins or other diseases which are known to relate to a protein and can be prevented or treated by stimulating immune response to the protein or inducing immune tolerance to the protein.
In some embodiments of the present invention, the antigen is a cancer antigen. As used herein, “cancer antigen” is a compound relating to tumor or cancer cell surface, for example, a peptide or a protein, and when the antigen is expressed on the surface of an antigen presenting cell, it can provoke an immune response. Cancer antigens can be obtained from cancer cells by preparing crude extract of cancer cells, for example, as described in Cohen P A, et al., (1994) Cancer Res 54: 1055-8, by partially purifying the antigens, by recombination technology, or by de novo synthesis of a known antigen. Cancer antigens include but are not limited to antigens that are recombinantly expressed, an immunogenic part of tumor or cancer, or a whole tumor or cancer. These antigens can be isolated or prepared recombinantly or by any other methods known in the art.
The terms “cancer antigen” and “tumor antigen” can be used interchangeably, and refer to antigens differentially expressed by cancer cells and can thereby be exploited to target cancer cells. Cancer antigens are antigens capable of stimulating significant tumor-specific immune response. Some of these antigens are encoded by normal cells, although not necessarily expressed. These antigens can be characterized as those which are normally silent (i.e., not expressed) in normal cells, those that are expressed only at certain stages of differentiation, and those that are temporally expressed (e.g., embryonic antigens and fetal antigens). Other cancer antigens are encoded by mutant genes, such as oncogenes (e.g., activated ras oncogenes), suppressor genes (e.g., mutant p53), or are fused proteins resulting from internal deletions or chromosomal translocations. Still other cancer antigens can be those encoded by virus genes such as those carried by RNA and DNA tumor viruses. Examples of tumor antigen include MAGE, MART-1/Melan-A, gp100, dipeptidyl peptidase IV (DPPIV), adenosine deaminase-binding protein (ADAbp), cyclophilin b, colorectum-associated antigen (CRC)-C017-1A/GA733, carcino-embryonic antigen (CEA) and its immunogenic epitopes CAP-1 and CAP-2, etv6, am11, prostate-specific antigen (PSA) and its immunogenic epitopes PSA-1, PSA-2, and PSA-3, prostate-specific membrane antigens (PSMA), T-cell receptor/CD3-ζ chain, MAGE-family of tumor antigens (e.g., MAGE-A1, MAGE-A2, MAGE-A3, MAGE-A4, MAGE-A5, MAGE-A6, MAGE-A7, MAGE-A8, MAGE-A9, MAGE-A10, MAGE-A11, MAGE-A12, MAGE-Xp2 (MAGE-B2), MAGE-Xp3 (MAGE-B 3), MAGE-Xp4 (MAGE-B4), MAGE-C1, MAGE-C2, MAGE-C3, MAGE-C4, MAGE-C5), GAGE-family of tumor antigens (e.g., GAGE-1, GAGE-2, GAGE-3, GAGE-4, GAGE-5, GAGE-6, GAGE-7, GAGE-8, GAGE-9), BAGE, RAGE, LAGE-1, NAG, GnT-V, MUM-1, CDK4, tyrosinase, p53, MUC family, HER2/neu, p21ras, RCAS1, α-fetoprotein, E-uvomorulin, α-catenin, β-catenin and γ-plakoglobin, p120ctn, gp100Pme1117, PRAME, NY-ESO-1, cdc27, adenomatous multiplepolyposis coli protein (APC), calspectin, connexin 37, Ig-idiotype, p15, gp75, GM2 and GD2 gangliosides, viral products such as proteins of human papilloma virus, Smad family of tumor antigens, 1mp-1, P1A, EBV-encoded nuclear antigen (EBNA)-1, brain glycogen phosphorylase, SSX-1, SSX-2 (HOM-MEL-40), SSX-1, SSX-4, SSX-5, SCP-1 and CT-7 and c-erbB-2.
Cancers or tumors and tumor antigens associated with such tumors (but not exclusively) include acute lymphoblastic leukemia (etv6; am11; cyclophilin b), B cell lymphoma (Ig-idiotype), neuroglioma (E-uvomorulin; α-catenin; β-catenin; γ-plakoglobin; p120ctn), bladder cancer (p21ras), biliary cancer (p21ras), breast cancer (MUC family; HER2/neu; c-erbB-2), cervical cancer (p53; p21ras), colon cancer (p21ras; HER2/neu; c-erbB-2; MUC family), colorectal cancer (colorectal-associated antigens (CRC)-C017-1A/GA733; APC), choriocarcinoma (CEA), epithelial cell cancer (cyclophilin b), gastric cancer (HER2/neu; c-erbB-2; ga733 glucoprotein), hepatocellular cancer (α-fetoprotein), Hodgkin lymphoma (1mp-1; EBNA-1), lung cancer (CEA; MAGE-3; NY-ESO-1), lymphoid cell-derived leukemia (cyclophilin b), melanoma (p15 protein, gp75, oncofetal antigen, GM2 and GD2 gangliosides), myeloma (MUC family; p21ras), non-small cell lung cancer (HER2/neu; c-erbB-2), nasopharyngeal cancer (1mp-1; EBNA-1), ovarian cancer (MUC family; HER2/neu; c-erbB-2), prostate cancer (prostate-specific antigen (PSA) and its immunogenic epitopes PSA-1, PSA-2, and PSA-3; PSMA; HER2/neu; c-erbB-2), pancreatic cancer (p21ras; MUC family; HER2/neu; c-erbB-2; ga733 glucoprotein), renal cancer (HER2/neu; c-erbB-2), squamous cell cancers of cervix and oesophageal (viral products such as human papilloma virus proteins), testicular cancer (NY-ESO-1), T-cell leukemia (HTLV-1 epitope), and melanoma (Melan-A/MART-1; cdc27; MAGE-3; p21ras; gp100Pme1117).
In some embodiments of the present invention, the malignant tumors include but are not limited to skin basal cell cancer, biliary tract cancer, bladder cancer, bone cancer, brain and CNS cancer, breast cancer, cervical cancer, choriocarcinoma, colorectal cancer, connective tissue cancers, cancers of digestive system, endometrial cancers, esophageal cancer, eye cancer, head and neck cancers, stomach cancer, neoplasm in epithelial cells, kidney cancer, larynx cancer, leukemia, liver cancer, lung cancer (e.g., small cell and non-small cell lung cancers), lymphoma including Hodgkin and non-Hodgkin lymphomas, melanoma, myeloma, neuroblastoma, mouth cancers (e.g., lip, tongue, oral cavity cancers), ovarian cancer, pancreatic cancer, prostate cancer, retinoblastoma, rhabdomyosarcoma, rectal cancer, renal cancer, respiratory system cancers, sarcomas, skin cancer, gastric cancer, testicular cancer, thyroid cancer, uterine cancer, urinary system cancer, and other cancers and sarcomas. The tumor-associated antigens can be for example a-fetoprotein of liver cancer, tyrosinase-related protein-2 of melanoma, etc.
In the present invention, the infectious diseases can be for example infectious diseases relating to bacteria, fungi, viruses and parasites.
The viruses include but are not limited to: Retroviridae (e.g., human immune defective viruses, such as HIV-1 (also referred to as HDTV-III), LAVE or HTLV-III/LAV, or HIV-III, as well as other isolates, for example, HIV-LP; Picornaviridae (e.g., polio viruses, hepatitis A viruses; enteroviruses, human coxsackie viruses, rhinoviruses, human enteric orphan viruses); Calciviridae (e.g., strains that cause gastroenteritis); Togaviridae (e.g., Equine encephalitis virus, Rubella virus); Flaviridae (e.g., Dengue virus, encephalitis viruses, Yellow fever virus); Coronaviridae (e.g., coronaviruses); Rhabdoviridae (e.g., vesicular stomatitis viruses, Rabies viruses); Filoviridae (e.g., Ebola viruses); Paramyxoviridae (e.g., parainfluenza viruses, mumps viruses, measles viruses, respiratory syncytial viruses); Orthomyxoviridae (e.g., influenza viruses); Bungaviridae (e.g., Hantaan viruses, parasitic aeginetia viruses, phleboviruses and nairo viruses); Arenaviridae (hemorrhagic fever viruses); Reoviridae (e.g., reoviruses, orbiviruses and rotaviruses); Birnaviridae; Hepadnaviridae (hepatitis B virus); Parvoviridae (parvoviruses); Papovaviridae (papilloma viruses, polyoma viruses); Adenoviridae (most adenoviruses); Herpesviridae (herpes simplex viruses (HSV)1 and 2, varicella herpes zoster viruses, cytomegalovirus (CMV), herpes virus; Poxviridae (variola virus, cowpox virus, poxvirus); and Iridoviridae (e.g., African swine fever virus); as well as unclassified virus (e.g., A hepatitis factors (thought to be a defective trabants of hepatitis B virus), non-A non-B hepatitis factors (class 1=internal transmitted; class 2=parenterally transmitted (i.e., hepatitis C); Norwalk virus and related viruses, as well as astroviruses).
The bacteria include Gram-negative and Gram-positive bacteria, both of which can be used as antigens in vertebrates. Gram-positive bacteria include but are not limited to Pasteurella species, Staphylococcus species, and Streptococcus species. Gram-negative bacteria include but are not limited to Escherichia coli, Pseudomonas species, and Salmonella species. Examples of infectious bacteria include but are not limited to Helicobacter pyloris, Borrelia burgdorferi, Legionella pneumophila, Mycobacteria sp. (e.g., Mycobacterium tuberculosis, Mycobacterium avium, Mycobacterium intracellulare, Mycobacterium kansasii, Gordon mycobacterium), Staphylococcus aureus, Neisseria gonorrhoeae, Neisseria meningitidis, Listeria monocytogenes, Streptococcus pyogenes (Group A streptococcus), Streptococcus agalactiae (Group B streptococcus), Streptococcus (viridans group), Streptococcus faecalis, Streptococcus bovis, Streptococcus (anaerobius), Streptococcus pneumoniae, pathogenic Campylobacter sp., Enterococcus sp., Haemophilus influenzae, bacillus anthracis, Corynebacterium diphtheriae, Corynebacterium sp., Erysipelothrix rhusiopathiae, Clostridium perfringens, bacillus tetani, Enterobacter aerogenes, Klebsiella, Pasteurella multocida, bacteroides sp., Fusobacterium nucleatum, Streptobacillus moniliformis, Treponema pallidum, Treponema pertenue, Leptospira, Rickettsia, Actinomyces Israeli. 
Examples of fungi include Cryptococcus neoformans, Histoplasma capsulatum, Coccidioides immitis, Blastomyces dermatitidis, Chlamydia trachomatis, Candida albicans. 
Examples of parasites include Plasmodium spp. such as Plasmodium falciparum, Plasmodium malariae, Plasmodium ovale, Plasmodium vivax, as well as Toxoplasma gondii. Blood-porne and/or tissues parasites include Plasmodium spp., Babesia microti, Babesia divergens, Leishmania tropica, Leishmania spp., Leishmania Braziliensis, Leishmania donovani, Trypanosoma gambiense, Trypanosoma rhodesiense (African sleeping sickness), Trypanosoma cruzi (Chagas' disease), and Toxoplasma gondii. 
most of protein antigens relating to infectious diseases have been disclosed. For example, surface antigen proteins of hepatitis B, HIV-associated proteins of AIDS, membrane proteins of most bacteria, wall-held proteins of fungi, parasite proteins of different stages of development process of parasites.
In the present invention, the autoimmune diseases include but are not limited to rheumatoid arthritis, ankylosing spondylitis, variable skin diseases, Crohn's disease, multiple sclerosis, systemic lupus erythematosus (SLE), autoimmune encephalomyelitis, myasthenia gravis (MG), Hashimoto's thyroiditis, Goodpasture's syndrome, pemphigus (e.g., Pemphigus Vulgaris), Grave's disease, autoimmune hemolytic anemia, autoimmune Thrombocytopenic Purpura, scleroderma with anti collagen antibodies, mixed connective tissue disease, polymyositis, pernicious anaemia, idiopathic Addison's disease, autoimmune-associated sterility, glomerulonephritis (e.g., crescent glomerulonephritis, proliferative glomerulonephritis), bullous pemphigoid, Sjogren's syndrome, insulin resistance, and autoimmune diabetes mellitus, etc. The autoantigens relating to some autoimmune diseases are disclosed, for example, islet beta-cell antigen of type I diabetic pancreas, nerve sheath cell antigens of multiple sclerosis, Pso p27 of psoriasis, hsp90 of Rheumatoid arthritis, CUZD1 and JP2 of Crohn's disease, etc.
In the present invention, living cells or apoptotic cells can be used according to purpose of using cells. For example, when human immune response is to be activated for prevention or treatment of tumors or infectious diseases, living cells can be used; while when immune tolerance against autologous or extraneous antigens is to be induced for prevention or treatment of autoimmune diseases, apoptotic cells can be used (because stable apoptotic cells have properties of inducing immune tolerance).
The method for preparing the apoptotic cells is well known in the art, for example, the cells coupled with protein can be irradiated with ultraviolet ray to produce apoptotic cells.
In the present invention, for the above uses, autologous cells or allogeneic cells can be used. Autologous cells are preferably used for prevention or treatment of autoimmune diseases.
In the present invention, the subject refers to a mammal, for example, human, dog, monkey, mouse, rat, bovine, equine, etc.
In the present invention, the effective amount refers to a dose that can achieve treatment, prophylaxis, alleviation and/or relief of the diseases or disorders as disclosed in the present invention.
Beneficial Effects of the Invention
In the present invention, a bifunctional cross-linking agent is used to couple a protein and a cell conveniently and effectively, to obtain a protein-cell conjugate, which can be used for many purposes according to the properties of the protein and the cell of the obtained conjugate, for example, the target ability or antigen presentation of the cell can be utilized to exert the better immunization of protein, and in the meantime, since a very small amount of protein carried by the cell can achieve a similar or better effect than a large amount of free soluble protein used for direct immunization, side-effects of direct immunization with large amount of protein can be avoided.